Cut the fish into strips about 1-inch wide, and pat them dry with a paper towel.
Place the oil in a large frying pan or saucepan over medium-high heat. The oil should be about 1-inch deep. Warm the oil to about 350°F (180°C), using an instant-read thermometer to check the temperature.
While the oil is heating up, heat a medium frying pan over medium heat. Once the pan is hot, place the tortillas in the pan, one by one, and heat both sides for about 45 seconds per side. Wrap the hot tortillas in a clean dishtowel to keep them warm.
Mix the cornmeal, salt and pepper together in a shallow dish large enough to hold the fish, and place the fish strips, one at a time, in the cornmeal. Roll them around to coat all sides.
Using tongs, place 4–5 pieces of coated fish in the hot oil, being careful not to splash yourself with oil. Cook the fish for 2 minutes on one side, and then flip and cook for an additional 1–2 minutes on the other side. Once the fish is cooked through and crispy, remove them with tongs or a slotted spoon and place them on a plate covered with paper towel to drain it. Repeat the process until all the fish is cooked. You may have to bring the oil back to temperature between batches.